ELECTRICAL AND MAGNETIC PROPERTIES OF ORGANIC SOLIDS.
Abstract
The study of the E.P.R. spectra of the isoalloxazine semiquinones was extended to neutral and basic pH. The data demonstrate that the unpaired spin density distribution of the neutral radical is identical to that of the acid form, thus showing that the proton added to the molecule in going from neutral to acid pH does not interact with the unpaired electron. Flavin-phenol complexes in neutral solution were found to have a 1:1 flavin:phenol ratio, while crystalline complexes obtained from such solutions display a 1:2 ratio. Stability constants of the complexes range roughly from 1 to 250. Neutral complexes are much more stable than acid complexes. Charge transfer does not contribute significantly to the stabilization of the acid complexes. It was found that hydroiodic acid can reduce isoalloxazine derivatives to the semiquinone level. The electrical and magnetic properties of single crystals of 1:1 charge transfer complexes of protonated flavins and phenols were investigated. EPR results indicate that complete electron transfer processes can occur at lattice imperfection sites which are produced either during the crystallization process or by removal of solvent from already-formed crystals. The unpaired spins so produced behave as localized, doublet state, free radicals.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 27, 1964
- Accession Number
- AD0610102
Entities
People
- Gordon Tollin
Organizations
- University of Arizona